1. Field of the Invention
The present invention relates to medical devices. Some embodiments relate to a bone anchor for securing body tissue to bone.
2. Description of the Related Art
There are several medical procedures where a surgeon needs to attach soft tissue such as tendons or other soft connective tissue to bone. One common example is a torn rotator cuff, where the supraspinatus tendon has separated from the humerus causing pain and loss of ability to elevate and externally rotate the arm. To repair a torn rotator cuff, typically a surgical procedure is used to suture the torn tendon to the bone using a variety of methods. Some procedures utilize large incisions and involve complete detachment of the deltoid muscle from the acromion. Small diameter holes are made in the bone for passing suture material through the bone to secure the tendon. Such large incision procedures are traumatic, causing prolonged pain and recovery time. Other procedures make small incisions and use arthroscopic techniques to attach sutures using either small diameter holes or a bendable tine. Other injuries requiring similar techniques include biceps tendonitis (e.g., a biceps tenodesis procedure) and a torn ACL.
Currently, there are various staple and anchor devices for attaching soft tissue to bone. However, many of these devices suffer from low pull-out strength, a lack of adequate suture attachment sites, a requirement to tie complicated knots with the sutures, complicated threading routines, a failure to assist the surgeon in positioning soft tissue into contact with bone prior to suturing to maximize bonding of the soft tissue to bone, and an overall difficulty in physically handling the devices during surgery.
Generally, injury to joints such as the shoulder and knee involve the tearing or separation of ligaments from their natural position on the bone. The injury leads to a chronic instability in the joint which requires surgical intervention. Modernly, the surgery involves use of one or more arthroscopic devices. These devices include surgical cannulas through which a camera or surgical device are passed. The arthroscopic methods usually involve reduced trauma to the patient than previous methods and can predict a faster recovery.
In brief, the surgical procedures involve visualization and localization of the damage, preparation of the bone surface, implantation of a soft tissue anchor, and suturing of the tissue to the anchor. By tightly contacting the ligament or other soft tissue to a properly prepared bone surface, the two materials bond during the healing process.
However, it is difficult to manipulate sutures within the surgical site using arthroscopic techniques. In some techniques, such as knot tying, it is difficult to properly adjust the tension of the suture while tightening the knot. Thus, there is a need for improved methods and devices that allow easy arthroscopic repair of soft tissue injuries. It is understood that the methods and devices described herein are applicable to other surgical procedures, whether the surgery is arthroscopic or open.